1. Field of the Invention
The present invention relates to the handling of loads placed on pallets. More particularly, the present invention relates to apparatus for sealing a load, such as cartons of goods or produce, placed on a pallet. One useful application of the present invention is the sealing and preservation of produce such as fruits and vegetables within an artificial environment for shipping and storage, where the produce is packed in cartons which are, in turn, stacked on pallets for shipping.
2. Description of the Related Art
The movement of produce from the field or orchard to the marketplace is a primary concern for farmers and merchants. To ensure freshness for the consumer, produce needs to be harvested, packed, transported, unloaded, and, finally, displayed for sale. Depending upon the location of the marketplace, this process may also require storing the produce for periods of time while awaiting transportation, unloading, or displaying. The storage may take place in a refrigerated warehouse or storeroom. If the marketplace is distant from the field or orchard, then the transportation itself of the produce requires a relatively long period of time. Indeed, for foreign markets, it may be several weeks between harvest by a farmer and end purchase by a consumer.
It is during these periods of storage and transportation that are of primary concern for farmers and merchants. If not handled properly, produce will spoil, and profits will sag. Accordingly, time, money, and energy are dedicated to improving the packing and the preservation of produce to maximize the quality of produce for market.
When harvested, produce is typically placed in cartons which, in turn, are stacked on pallets. This may take place in the field or orchard or in a nearby warehouse. When palletized, the cartons of produce may then be easily moved by forklift to refrigerated tractor-trailer rigs and, if needed, to refrigerated containers for loading onto trains and ships.
To enhance the preservation of produce when on a pallet, an oxygen-depleted artificial atmosphere may be created by wrapping either individual cartons of produce or an entire stack of cartons of produce in plastic film. Oxygen levels within the wrapped carton or stack of cartons may then be minimized, for example, by injecting nitrogen into or by evacuating gas from within the wrapped stack of cartons.
One example of a conventional approach to preserving produce is disclosed in U.S. Pat. No. 5,945,147 entitled “Method for Packaging Fresh Perishable Food” by James A. Borchard (who is also the inventor in the present application), the entire disclosure of which is incorporated herein by reference.
Other conventional approaches entail covering a stack of cartons on a pallet with a bag and then sealing bottom edges of the bag to create a substantially hermetic environment. Conventional systems perform this bagging process in assembly-line fashion using a conveyor. Pallets of produce are moved on the conveyor through successive stages of placing a bag over a stack of cartons, sealing the opening of the bag with adhesive tape, and applying gas to preserve the produce within the bag. Each stage requires manual labor, thereby increasing cost. In addition, the bagging process is carried out in a refrigerated warehouse in which costs are directly proportional to the amount of floor space required for the preservation operation.
In addition to preservation, cartons of produce may also require fumigation. Conventional approaches to fumigating cartons of produce entail moving pallets of produce into large chambers, fumigating the chamber, and then removing the pallets from the chamber. Once again, large warehouse space and substantial manual labor are required.
In view of the foregoing, there remains a need in the art for systems and methodology that seal and, if desired, preserve a load, for example, a stack of cartons containing produce, placed on a pallet in an efficient and cost-effective manner.